Shouldn't the Windows version work with Linux? When I build the package, I choose the Windows/Linux option. I don't have Linux at the moment so I can't test it. I will look into this when I build the new release. Come to my discord and I can have you test the builds and work with me if you want.
No, the Linux version is it's own version. The Linux executable is packaged properly right now and it works but somehow you have told Itch.io that there is only a Windows, Android; and Mac version because that's the only platforms listed. Most likely just have to check a box with them although I have never published a game with Itch.io. The issue currently isn't that Linux gamers can't play Ripples but that if they go by the platforms listed by Itch.io they may think that they can't because no Linux version is listed.